Plains Of The Altiplano, Bolivia, Spanish Salar De Uyuni Mirror

Rear-view mirrors are widely used in and on vehicles (such as automobiles, or bicycles), to allow drivers to see other vehicles coming up behind them. Some motorcycle helmets have a built-in so-called MROS (Multiple Reflective Optic System): a set of reflective surfaces inside the helmet that together function as a rear-view mirror. On rear-view sunglasses, the left end of the left glass and the right end of the right glass work as mirrors.
Two-way versus one-way mirrors and windows